Substituted .beta.-ketoanilide compounds which are useful for the control of insect pests are described in a related U.S. patent application. The related application discloses that substituted .beta.-ketoanilide compounds may be prepared by reacting a substituted aniline with a lactone such as dimethylketene .beta.-lactone dimer. However, dimethylketene .beta.-lactone dimer is not entirely satisfactory because it is a persistent lachrymator.
U.S. Pat. No. 3,072,724 discloses that certain .beta.-ketoamide compounds may be prepared by reacting a nitrogen containing compound with a tetraalkyl-1,3-cyclobutanedione. However, that patent specifically discloses that aromatic amines such as aniline do not react with tetraalkyl-1,3-cyclobutanediones to form .beta.-ketoamides. In addition, Haske, et al in the Journal of Organic Chemistry, 26, pp. 4340-4344 (1961) disclose that it is difficult to prepare 2,2,4-trimethyl-3-oxovaler-anilide from aniline and tetramethyl-1,3-cyclobutanedione.
It is, therefore, an object of the present invention to provide a new and efficient process for the preparation of substituted .beta.-ketoanilide compounds which avoids the use of dimethylketene .beta.-lactone dimer and overcomes the difficulties described in the art associated with the use of tetraalkyl-1,3-cyclobutanediones.